After years of buying the glass tube heaters and even later trying to control them with exterior thermostats, I finally invested in one of these. Great power for my 90 gallon tank, and having the temperature and settings outside the tank and visible can’t be beat. No more algae on the heater making it impossible to check the temp setting or see the on light. The temp sensor can be mounted on the other end of the tank so you know the entire tank is the right temperature. You can see the actual temperature and the set point at all times with big red numbers.I discovered a problem with tube heaters, when mounted vertically, they seem to cycle on and off because the heater heats the thermostat. So that means you don’t get the full name plate power of the heater because it cycles too much. No problems like that here.One minor issue I’ve had which has not affected functionality: Occasionally, the thermostat will switch to Celsius. I don’t know if this happens randomly or my kids are messing with it, or it happens when the mains power cycles. But it happens some times. The set point remains set, which is good, but with the exchange between F and C, when set to C, it allows the temp to drop a degree F lower than what it is set to. No big deal, and I’m not sure why it happens. Maybe it is the cat bumping the buttons or something. And again, this has not affected functionality.Also, the suction cups are less than stellar, but you generally need to replace suction cups periodically anyway.